This invention relates to the treatment of organic compounds with liquid hydrogen fluoride (HF). In one aspect, it relates to removal of organic fluorides from organic materials containing organic fluorides. In one specific aspect, it relates to an improved process for the removal of alkyl fluorides from a low-boiling hydrocarbon such as propane.
In processes where fluorine-containing catalysts such as hydrogen fluoride and boron-trifluoride are used, small proportions of organic fluorine-containing by-products are formed. These processes can involve such reactions as isomerization, polymerization, alkylation, and disproportionation of relatively low-boiling hydrocarbons.
In alkylation processes using an HF catalyzed reaction in which alkyl fluorides are formed, the removal of these fluoride contaminants from the propane produced by the alkylation using only conventional distillation steps is practically impossible. The presence of the alkyl fluorides in the product propane is objectionable for many of the end uses of the propane. For example, when organic fluoride is present in liquefied proprane to be used as LPG fuel, the combustion products contain HF which is produced by the combustion of the organic fluoride present in the propane. This produced HF will enter the atmosphere in the combustion gases as a hazardous contaminant of the environment. There have been many proposals of methods for the removal of organic fluorides from the by-product propane in a process such as HF catalyzed alkylation. Many of these processes are expensive but are quite adequate. It is, however, always of interest when a hitherto unknown process for the removal of alkyl fluorides from propane is brought forth, especially when the process requires relatively simple alteration to standard operating apparatus and process.
It is, therefore, an object of this invention to provide a method for removing alkyl fluorides from the propane by-product of HF alkylation. It is another object of this invention to provide a propane by-product of HF alkylation that is considerably reduced in alkyl fluoride content.
Other aspects, objects and various advantages of this invention will become apparent upon reading the specification, the claims and studying the drawing attached hereto.